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Old April 10th, 2010, 08:28 AM   #1
HSRCanada
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MISC | Curves and bends

Aaahh, the Rockies, they are so ... mountainy! It wouldn't be cheap to just build straight through them right? So how does one calculate maximum safe speed for trains on curves? I know it has something to do with the radius, but when somebody tried to explain it to me they gave me some American website with imperial measurements and I got confused. Do you think a speed of 140 - 160 km/h is achievable in the Rockies for example? Thanks
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Old April 10th, 2010, 02:05 PM   #2
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Quote:
Originally Posted by HSRCanada View Post
Aaahh, the Rockies, they are so ... mountainy! It wouldn't be cheap to just build straight through them right? So how does one calculate maximum safe speed for trains on curves? I know it has something to do with the radius, but when somebody tried to explain it to me they gave me some American website with imperial measurements and I got confused. Do you think a speed of 140 - 160 km/h is achievable in the Rockies for example? Thanks
Basically the radii will increase with the square of the speed. For real HSR at least 4000m are needed
If no tilting trains are used then with 120km/h you need 625 m with 200km/h 1800 m.
By using tilting trains and or slanted curves you can go down to 450m and 1300 m respectively.
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Old October 11th, 2011, 12:21 AM   #3
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Quote:
Originally Posted by HSRCanada View Post
Aaahh, the Rockies, they are so ... mountainy! It wouldn't be cheap to just build straight through them right? So how does one calculate maximum safe speed for trains on curves? I know it has something to do with the radius, but when somebody tried to explain it to me they gave me some American website with imperial measurements and I got confused. Do you think a speed of 140 - 160 km/h is achievable in the Rockies for example? Thanks
Some basic values for curves with/without tilting:


The rough cornering speeds:

Conventional line with freight (radius, no tilt , 6% tilting)
<<notice there are tilting trains that surpass the 6% tilt described here

0.5km - 100km/h / 125km/h
1.0km - 150km/h / 180km/h
1.5km - 175km/h / 220km/h
2.0km - 190km/h / 240km/h
2.5km - 200km/h / 260km/h
3.0km - 210km/h / 280km/h
3.5km - 220km/h / 300km/h

High Speed line (more cant built into track or light tilting trains(1%?))

3.0km - 230km/h
3.5km - 270km/h
4.0km - 300km/h
5.0km - 360km/h
6.0km - 400km/h


Hope it helps ... and take this pics as a little example of how to go faster in tortuous terrain:

8% tilt as 170km/h


8% tilt at 228km/h (228 = ATP tolerance limit = 8km/h)



180km/h at maximum tilt in a otherwise 140km/h section


228km/h with almost no tilt at all
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Old September 18th, 2012, 08:13 AM   #4
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squealing more prevalent: why?

How come squealing by trains going through curves is so prevalent nowadays? What happened? Why has negotiating bends become so bad?
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Old September 18th, 2012, 11:14 AM   #5
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To answer the original question; judging from my knowledge of the rockies around Calgary, and assuming the valleys are broadly similar in geometry, a 200km/h line ought to be perfectly feasible, if they got the alignment right.
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Old September 18th, 2012, 01:59 PM   #6
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Quote:
Originally Posted by trainrover View Post
How come squealing by trains going through curves is so prevalent nowadays? What happened? Why has negotiating bends become so bad?
My guess is that modern trains all have either bolsterless bogies or bogies with rotational dampers. Both resist unwanted bogie rotation while in a straight line so they're great for high speed stability. The downside is that they also resist bogie rotation in curves. I think it is this dampening of the rotation that causes the squealing.
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Old November 10th, 2012, 06:46 PM   #7
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MISC | Examples of small railway curve radius

Does anyone know of any interesting examples of small railways curves?
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Old November 10th, 2012, 10:38 PM   #8
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This one in Chiasso, Switzerland, on an industrial track.
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Old November 11th, 2012, 07:32 PM   #9
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Alishan forestry railway...
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Old November 11th, 2012, 11:30 PM   #10
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Please post all new threads to the thread finder. This thread has a similar thread in the form of this thread so I have merged them.
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